A clear night sky is a wondrous mosaic of light -- full of tiny stars and planets and the ever-present moon. While amateur stargazers might not put too much thought into the specifics of individual stars, astronomers can glean plenty of information about celestial bodies using specialized instruments, computer programs and complex mathematical calculations. Among other functions, one instrument -- the photometer -- can give us quantitative information about a star’s brightness.

Photometers and Star Brightness

Photometers are instruments used to measure a star’s apparent brightness, or how bright the star is from an Earth reference point. Simple calculations can then be used to determine absolute brightness, which is the apparent brightness corrected for distance from Earth. Photometers can range from handheld versions costing thousands of dollars to much larger versions found in major observatories, such as the Multiband Imaging Photometer at the California Institute of Technology.

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About the Author

Robert Mullis is is a graduate of Liberty University with a bachelor's degree in biochemistry and a second degree in accounting. As a writer, he specialized in math, biology, chemistry, literature, and business.